The present invention pertains to the field of art involving installation assemblies for light sources that may be employed in illumination systems such as video-equipped endoscopes or borescopes.
In typical video-equipped endoscope and borescope systems, a high voltage white light source is required to illuminate a target in the object plane of the viewing optics. Generally, the white light generated from the light source is optically coupled to a viewing probe which is configured to transmit the light into a target area. The incident light reflected from the target is received by a viewing head of the probe which causes an image to be focused upon an imaging device within the probe. The imaging device receives the image and converts it into electrical signals to be processed. A more detailed description of such a system is provided in U.S. Pat. Nos. 4,532,918 to Wheeler and 4,539,586 to Danna et al.
The light source employed in typical video-equipped endoscope and borescope systems may be a conventional gas-filled flash lamp which is sometimes referred to as an arc discharge lamp. As is well known in the arts, the flash lamp includes a Quartz envelope that is filled with an inert gas such as xenon. When the lamp is triggered, it produces a high intensity flash of white light to ensure that the image received by the viewing probe accurately reflects the true target colors.
As a consequence of the high intensity operation of this type of lamp, a substantial amount of heat is generated. Proper operation of such lamp requires the use of heat sinks to dispose of the heat energy. In many cases, the heat sinks provide structural support for the lamp itself. The heat sinks may also provide an additional function, in that if properly arranged, they act as electrical conductors for connecting lamp electrodes to a power supply. In such an assembly, the electrical power supply leads are connected to the heat sinks to complete the power supply circuit of the lamp.
In most applications, and in particular, applications directed to video-equipped endoscope and borescope instruments, the lifetime of the lamp is substantially shorter in comparison to the lifetime of the instrument. Therefore, the lamp installation should be designed so that it can be easily replaced without having to dismantle a major portion of the instrument.
Typical lamp installations provide access to the lamp assembly, which may include the lamp itself, and the heat sinks surrounding the lamp. However, the assembly is ordinarily fastened to a support frame by screws or other fasteners. In addition, the electrical leads from the lamp power supply are fastened to the lamp or heat sink electrodes by screws. Such an arrangement frequently requires the use of special tools to remove the lamp assembly and replace it with another. Such a procedure may be a difficult and lengthy task particularly for a non-technical or inexperienced operator of the system. Therefore, expedient replacement of a failed lamp is generally not realized for many applications.
One of these applications involves the use of a video-equipped endoscope by a physician to view the internal body organs or cavity of the patient. Failure of a lamp while the probe is inside a patient's body can lead to extended patient discomfort and even trauma. In addition, failure of the lamp at this time usually results in the examination being aborted and can, under certain conditions, make removal of the probe difficult. Another shortcoming with conventional lamp installations is that the lamp assembly is required to cool down before manual replacement is practical.
A further shortcoming of a conventional lamp installation is that the heat sinks of the lamp assembly are rigidly mounted to the lamp itself. Therefore, thermal expansion of the heat sinks during operation may expose the lamp to physical stresses, contributing to the lamp's failure.